Ice: Sun’s on our side

Temperatures are just below freezing officially in Philly and have dropped to 28 at Pottstown and Trenton.

Meanwhile, some light rain has been prowling the area, and any rain is going to freeze on windshields and mailboxes for certain, and even on to some driveways.

However, it will have a hard time bonding onto any treated road surfaces, and not just because of the salt.

This is Feb. 9, and the sun – even though you can't see it – is becoming an ever-more powerful force, strong enough to have some affect on blacktop. It should help at least mitigate road icing during the day.

In February, the sun makes a big move to assert its power over the Northern Hemisphere.

Fred House, a Drexel University professor emeritus and solar-radiation expert, has estimated that on average,  the sun aims 329 watts per square meter to the top of the Earth's atmosphere above Philadelphia.

That occurs at quite a range, however, from 156 watts at the winter solstice to 484 watts at the summer solstice.

About 25 percent of that gain occurs in February, when the wattage increases from 208 watts on Feb. 1 to 280 at the end of the month.

Late in the day and at night, of course, the ballgame changes. Dark surfaces will retain some of the solar radiation for awhile, however, roads can ice over in a hurry once the sun calls it a day.

The days now are about two hours and 20 minutes longer than they were at the solstice.

The sun will keep gaining strength, and the days will lengthen, but as John Bolaris points out in his forecast, winter has plenty of life left.